1. Field of the Invention
Apparatus, systems and methods consistent with the present invention relate to downloading content, and more particularly content downloading in which a large amount of content, such as high definition (HD) content, is efficiently downloaded in accordance with a user's preference and the completion of the content downloading is reported to a user.
2. Description of the Prior Art
A video on demand (VOD) service provides video information requested by a user in real time. The VOD service is referred to as a customized video data service or a VOD reference system. The VOD service is a bidirectional service that does not receive a program in a unidirectional manner through the existing public network broadcasting or cable TV system, but receives desired content at a desired time in accordance with a subscriber's request. In addition, the VOD service provides various functions of play, stop, pause, fast forward, fast rewind, and playback at an arbitrary position. Examples of systems that use the VOD service include a high-speed backbone network, an access network, a set top box, and a multimedia database management system (DBMS). The high-speed backbone network connects a video server to a connection network. The access network connects the high-speed backbone network to the set top box. The set top box plays compressed digital video and audio that is transmitted by the video server, and sends the user's request to the video server. A large, optimized database storing video data and audio data is established in the video server in order to provide the video data or the audio data in real time. VOD may also be used in other applications, such as remote-control medical treatment, remote-control education, home banking, home shopping, and telecommunications.
Meanwhile, with the spread of digital broadcasting, demand for high definition (HD) content is increasing. However, current network bandwidth is insufficient for transmitting a large amount of HD content, which may be encoded at 8-10 megabits per second (Mbps). Spread of very high speed digital subscriber lines (VDSL) is at an initial stage in Korea, while asymmetric digital subscriber line (ADSL) networks are being established in other countries. Under the circumstances, it is predicted that it will take significant time to ensure sufficient quality of service (QoS) to allow a broadband network to transmit the HD content in real time to homes, and to stream the HD content at the actual speed of the network. Commercial downloading services have several problems because it takes a lot of time (12 hours in the case of 3 gigabytes (GB)) to download a large amount of HD content. Many methods for transmitting large amounts of content have been suggested to solve such problems.
Examples of the methods include a broadcasting Push VOD method based on a broadcasting network and a VOD method based on reserved downloading in an internet protocol (IP) network. The broadcasting Push VOD method has limitation in spread of service due to a limited frequency resource and a lack of customized content. Also, the above methods have different transmission networks. That is, the broadcasting network is unidirectional and has a broad transmission bandwidth for large-sized data while the IP network is bidirectional and has a narrow data transmission bandwidth. The VOD method based on reserved downloading in the IP network will mainly be discussed.
A representative example of the VOD method based on reserved downloading based on the IP network includes Korean Patent Unexamined Publication No. 2003-0075967 entitled “A VOD system Based on Reserved Downloading and a Service Method Thereof.” This related art VOD service will now be described in brief with reference to FIG. 1.
First, a user accesses a VOD server through an external computer system connected to a network. The user inputs information such as subscriber information, the number of times the content will be used, and a payment method, and reserves content downloading (S10). The VOD server generates a reserved code according to the information input by the user, and provides the generated reserved code to the subscriber (S20). At this time, the generated reserved code is matched with content use information, and is then stored in the VOD server. If the user intends to download the reserved content, the user externally calls an internal telephone terminal connected to a VOD set top box to actuate the VOD set top box (S30). The VOD set top box is supplied with a subscriber ID and the reserved code from the user (S40), and transmits them to the VOD server to request downloading of the reserved content (S50). The VOD server extracts the content use information from the reserved code to transmit corresponding content to a content supply server and commands downloading of the reserved content (S60). The content supply server encodes the corresponding content to include the content use information previously supplied from the user and downloads the corresponding content in the corresponding VOD set top box (S70). The VOD set top box stores the downloaded content in a storage medium (S80). Then, the subscriber identifies the stored content use information, and decodes the content to play the same.
However, the conventional VOD service has several problems.
First, only content reserved in advance can be downloaded, and downloading starts by the user directly inputting an ID and a reserved code with VOD set top box each time content is downloaded. For this reason, the conventional VOD service has little advantage in comparison with a pull downloading method based on immediate downloading. Also, the conventional VOD service is inconvenient in that the process takes a long time, and user information has to be input several times.
Second, there is no consideration for content downloading time and order. In the Push VOD method based on the broadcasting network, content is linearly downloaded in accordance with a content update order designated by a service provider. In the VOD method based on reserved downloading in the IP network, there is no function for adjusting a downloading order of a plurality of content if the content is reserved. For this reason, a problem arises in that the user is required to be in standby state to view desired content until downloading of content positioned prior to the desired content is completed. Moreover, since the content has a large size, the user must remain in a standby state for a long time. This is undesirable and it decreases the probability that the user will purchase the content.
Third, a problem arises in that the completion of the content downloading is not reported to the user. To identify either the time when the user can view desired content or content that can be played currently, the user may be required to check the status of the content downloading numerous times on the set top box, which is inconvenient.